4th internal biannual science meeting of the MLZ

Reconstruction of Magentization Density Distributions in Antiferromagnets with the new Polarized Neutron Diffraction Setup on POLI

27 Jun 2019, 10:00

20m

Library

Short talk Science group meetings 2

Speaker

Mr Henrik Thoma (Jülich Centre for Neutron Science JCNS at MLZ, Lichtenbergstr. 1, 85748 Garching, Germany)

Description

A dedicated polarized neutron diffraction (PND) setup, using a symmetric-field high Tc superconducting magnet with a maximal field of 2.2 T in combination with a ³He polarizer and Mezei-type flipper, has been developed at the instrument POLI. Each component is optimized by numerical simulations and the complete setup is successfully tested and calibrated.

This new PND setup was used to collected flipping-ratio (FR) data as function of the applied magnetic field and temperature for different antiferromagnetic compounds. A new advanced approach for the reconstruction of maximum entropy spin density maps from FR measurements is presented. Using this approach, 3D spin density maps can be built for the first time not only for the paramagnetic, but also for the antiferromagnetic phase. These 3D maps reveal new features compared to the results from conventional maximum entropy software and might be used to directly visualize magnetic multipoles.